DESCRIPTION (From Applicant's Abstract): Two recent developments in the social sciences have created an unusually rich opportunity for learning about substance use in adolescents and young adults. The first is a relatively new conceptual movement to examine problem behavior within more complex theoretical models. The second is a series of methodological advances that accommodate such complex models. This proposal is a continuation of a current data reanalysis project which has successfully applied these recent advancements to charting the development and social context of substance use and related problem behaviors. The continuation is designed to enhance our understanding of the roles of individuals, families, and the larger social context in the development of substance use and related deviant behaviors. This proposal expands our present work, supplementing our current data sets with the rich longitudinal panel data form the Monitoring the Future study, extending our analyses to young adulthood, and furthering the development of practical statistical techniques for studying change.